The present invention relates to a ski, or other board for gliding over snow, comprising rigid, distinct sidewalls, materialized by rigid reinforcing elements in the form of longitudinal strips.
This invention also relates to a process for making rigid, distinct sidewalls in the form of rigid reinforcing elements.
FIG. 1 of the accompanying drawings schematically shows, in transverse section, a conventional ski.
This ski presents;
a lower assembly comprising a sole 1 for gliding over snow, this sole 1 being bordered on either side by lateral metal edges 3 and 4; this assembly is surmounted by a fibrous reinforcing layer 2;
a core 5 surmounting this lower assembly, and bordered on either side by two rigid, longitudinal reinforcing elements, so called sidewalls 6, 7; and
an upper assembly comprising a fibrous reinforcing layer 15, surmounted by a plastic upper layer 10 for protection and decoration.
The two sidewalls 6, 7 lie above the lower assembly and their thickness is appreciable. The outer layer faces 8, 9 of the two rigid sidewalls 6, 7 form at least a part of the lateral faces of the ski.
The two lateral sidewalls 6, 7 are intended to:
directly transmit efforts from the user""s foot to the snow; in particular, they avoid xe2x80x9ccrushingxe2x80x9d of the different stacked components in the ski structure when the ski is subjected to stress; in effect, the force of impulsion generated by the skier, in particular when making a bend, tends to crush the ski between his/her feet and the snow; such crushing is translated by a loss of reaction time and a loss of energy, therefore by a loss of efficiency;
consolidate the strength of the metal edges within the ski structure; during use, the ski is often treated roughly by the presence of stones on the slopes; if the bearing above the edge is not firm enough, the edges subside or are torn in the event of considerable shock;
reinforce the ski structure in bending and in torsion, with lateral sidewalls 6, 7 presenting a high Young""s modulus; the stiffness is improved and improved resistance to breaking is obtained;
reinforce the resistance of the sidewalls of the ski to abrasion; the sidewalls of an alpine ski are subjected to the abrasion of the snow, to wear by friction against obstacles encountered on the slope (trees, rocks, . . . ) and to the aggression of the edges of the other ski of the pair;
participate in the aesthetic appearance of the ski; the sidewalls of the ski are a zone visible to all.
A conventional ski therefore comprises sidewalls, or lateral reinforcing elements, or rigid longitudinal reinforcing elements, located on either side of a central core and disposed above the metal edges.
These longitudinal elements may present a length substantially equal to, or shorter than, the supporting length of the ski. Similarly, the height of these longitudinal elements may correspond to the total height of the ski or may be less than this height.
These longitudinal elements thus respond to a need for consolidation of at least one zone of the ski subjected to considerable pressures or stresses.
It is known, for example by U.S. Pat. Nos. 3,967,992, 4,093,268 and 4,455,037, to make skis with reinforcing elements corresponding in dimensions to the lateral surfaces of the skis, i.e. having substantially the length and height of the ski.
Other intermediate solutions comprising localized reinforcing elements exist, for example as disclosed in Applicant""s Patents FR-2,683,734 and FR-2,703,915.
These lateral reinforcing elements are of different natures, and different processes enable them to be obtained.
For producing skis or like boards comprising metallic lower edges, two forms of reinforcing elements are found at the present time:
a stratified composite, with thermosettable resin based on phenol or melamine, for example,
an extruded then injected thermoplastic polymer material, such as Acrylonitrile-Butadiene-Styrene (A.B.S.) for example.
It is an object of the present invention to provide a ski, or other snow board, of which the characteristics are optimized by the use of improved lateral reinforcing elements.
The two lateral and longitudinal faces of a ski, or other snow board, are constituted by distinct, rigid, longitudinal elements called xe2x80x9csidewallsxe2x80x9d.
According to the present invention, the ski or other snow board is characterized in that these sidewalls comprise corrosion-proof metal particles incorporated therein and distributed in their structure.
These particles or inclusions may typically be metallic balls with a maximum diameter of 100 xcexcm, or metallic flakes whose length may vary between 5 and 100 xcexcm, and they are arranged discretely in the structure of said sidewalls. They are preferably made of a noble metal of relatively low density with respect to steel. Titanium or zirconium, of shiny white appearance, or gold, of shiny gold appearance, may for example be cited by way of metal used for these inclusions.
According to a second aspect of the invention, a process for producing rigid, distinct sidewalls intended for a ski or snow board comprises covering a thin sheet of paper with a layer of thermosettable resin, sprinkling this layer of thermosettable resin with metallic particles, repeating these latter two steps a number of times in order to obtain a stack of coated sheets, compressing this stack and triggering off polymerization of the resin, and cutting out the stack to the dimensions of the sidewalls.
According to a third aspect of the invention, a process for producing rigid, distinct sidewalls for a ski or other snow board comprises the steps consisting of incorporating metallic particles with the granules of polymer materials, extruding them and cutting out the molded plates obtained to the dimensions of the sidewalls.